In British English slang, particularly of north-west England this means 'lucky' or more accurately 'flukey'. It is usually applied to someone else who has just had a particular piece of outrageous or undeserved luck.

It is typically used with this meaning by young men and schoolboys throughout the north-west of England, not just Liverpool and Merseyside, but also Cheshire, etc. However, the usage can occur in other regions of England as well. It has been used to have this meaning throughout most of the period since at least the end of World War Two.

1. "Rooney fluffed the kick and then the ball ricocheted off the back of the defender's head into the net! The jammy bastard!"

2. Dave: "Hey, Gaz, you was late to class for the third time in a row, innit, how come you don't have detention?

Gaz: "Strickland was, like, too busy chewin' out some other sap and didn't notice, so I got away with it!"

1. A gun or firearm
2. A penis; a dick or schlong
3. (Usually plural) pajamas

1. "Pulled out the jammy, aimed it at the sky
He yelled, 'Stick 'em up!' and let two fly" - "Paul Revere" by the Beastie Boys
"'Cause I pull out my jammy and squeeze off six
My pistol is loaded - I shot Betty Crocker" - "Rhymin and Stealin" by the Beastie Boys
"Pulled out the jammy and like a mirage
A sissy like that got out of Dodge" - "8 Ball" by N.W.A.

2. "Pulled out the jammy and killed the punanny" "It Was A Good Day" by Ice Cube